When a computer boots up, or sometimes while the computer is operating, the computer may perform diagnostic and other preliminary tasks. These diagnostic tasks may test whether the internal memory (e.g., RAM, ROM) is operating correctly, whether internal or external peripherals such as drives or printers are working, whether parts of the computer system are operating correctly, whether wired or wireless network or other input/output (I/O) connections may be made, or whether the battery (in a laptop computer or a backup battery for a system component, for example) is working and how well.
Where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.